Document stacking apparatus



June 13, H. D S JR DOCUMENT STACKING APPARATUS Filed Aug. 25, 1965 Fig. 1.

2 Sheets-Sheet 1 INVENTOR.

DAN/EL H. 0A V/S, JR. BY

ATTORNEY.

DOCUMENT STACKING APPARATUS 2 Sheets-Sheet 2 l E g 60 Filed Aug. 25, 1965 5 6 5) I I n.

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which is located behind the United States Patent 3,325,165 DOCUMENT STAQCKKNG APPARATUS Daniel H. Davis, Jr., Dearborn, Mich., assignor to Burroughs Corporation, Detroit, Mich, a corporation of Michigan Filed Aug. 25, 1965, Ser. No. 482,459 45 Claims. ((31. 27l--71) This invention relates generally to document handling apparatus and, more particularly, to a high speed apparatus for automatically stacking and edge aligning sheets as they enter a bin.

In transporting documents of relatively thin material on edge at extremely high speeds to a hopper or bin, such as is performed with business machine document sorting apparatus, it has been found extremely difiicult to stack the documents continuously and uniformly.

A stacking mechanism is preferably arranged so that at the instant an incoming sheet reaches a predetermined position in the stacking bin, usually at the registration edge of the bin, the sheet will be removed from the path of the next incoming sheet and deposited on or against a stack support or stack follower. The stack is usually formed against a bias of the support or follower. One known system for such stacking of sheets in a bin or hopper includes sheet deflecting apparatus positioned adjacent the bin inlet for moving sheets broadside and on edge out of the path of travel of succeeding sheets entering the bin and toward a stack. Apparatus for performing this function may comprise pneumatic means for providing an air stream which impinges on a sheet having just entered the bin so as to deflect it toward others in the stack.

Because the deflecting device is oftentimes not in itself sufiicient to stack the sheets uniformly, other apparatus is provided for accepting the deflected sheets and relaying them quickly to a secure position in the stack. This additional apparatus may include one or more driven paddle wheels or impellers which are disposed along the side or sides of the bin to entrain the edges of incoming sheets and direct the documents to the stack.

Apparatus utilizing such paddle wheels is disclosed and claimed in an application of William Von Glahn, Ser. No. 369,573, now Patent Number 3,220,724, entitled Sheet Stacker which is assigned to the same assignee as the present invention. In that application, two adjacently disposed paddle wheels are employed to assist in the stacking operation. The first paddle wheel is positioned near the entrance to a stacking bin and serves to entrain the trailing edges of sheets pneumatically deflected toward the Wheel and to relay the sheets to a second paddle wheel first paddle wheel in the direction of sheet travel in the bin. The function of the second paddle wheel is to facilitate the uniform stacking of sheets by further urging the sheets toward others in the stack and keeping the sheets from retrogressing into engagement with the first paddle, wheel, under the bias of the stack follower, and thereby jamming the apparatus at the entry of the bin. The second paddle wheel thus functions as a power-driven keeper.

In high speed document handling apparatus the stack accumulates very rapidly and the documents tend to press back against the rotating keeper and, in the previously known art, the teeth thereon may beat against the edges of sheets stacked in the bin and, thus, occasionally may impart a lifting motion to the sheets to cause them to creep out of the uniform stack. This is particularly true when the sheet stacker is in an idling condition and no sheets are being added to the stack. Also, when the stacker is idling, the beating of the teeth of the second paddle wheel against the sheets may cause the edges thereof to be unduly worn.

Therefore, it is an object of the present invention to promote the uniform and eflicient stacking of documents by improving a stacker bin of the type having one or more rotating members for directing documents from the stacker bin entrance to the stack.

It is another object of the present invention to reduce Wear on the edges of documents being stacked in a stacking bin.

In accordance with the foregoing objects, the present invention, for use in a bin for stacking documents broadside on edge against a biased stack follower and having means for propelling the documents toward the stack, comprises the improvement of a power-driven rotating keeper in cylindrical form and having a regular polygonal cross-section for engaging the edges of said documents, for further directing the documents toward the stack and for preventing the documents from retrogressing into the propelling means.

Other objects and features of the invention will be specifically pointed out or will become apparent when referring to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a plan view of a document transporting and stacking apparatus incorporating the present invention.

FIG. 2 is a vertical sectional view taken along the line 2-2 of FIG. 1.

FIG. 3 is an enlarged fragmentary view of the document stacking bin utilizing the present invention.

Referring to the drawings, a portion of a document handling and stacking mechanism 10 incorporating applicants invention is shown in FIG. 1. Sheets, which may be punched cards or bank checks to be processed, are supported edgewise between guide members 12 and 14 and are fed singly in succession to a tensioned cotton belt 16 and pressure rollers 13 and then to a turnaround sheet feeding drum 2h cooperating with pressure rollers 22. From the drum 253, the sheets are stacked into a bin 24 in the same order in which they were processed. The above apparatus is mounted on a stationary base plate or casting 25 having rigidly fixed thereto and elevated slightly thereabove a vibratable bin floor plate 23 which is relatively movable with respect to the stationary base plate 26 for sheet stacking and alignment purposes. The movable floor plate 28 is vibrated in a reciprocating rectilinear path by an electromagnetic jogger (not shown).

The illustrated sheet stacking apparatus includes a stationary sheet guide plate or rail 36 which defines part of one side of the bin 24. The bin also includes parallel front and rear walls 32 and 34, respectively, and a movable stack follow-er or back-up member 36, providing an expansible bin. The back-up member 36 is sup-oprted at one end thereof on a bushing 38 which is slidable along a stationary guide rod as. A spring 42 is provided to bias the stack follower 36 toward the stationary guide plate of the bin. The force of this spring is overcome by the movement of back-up member 36 caused by the pressure of accumulating sheets within the bin 24.

The stationary bin side plate 30 extends rearwardly of the bin rear Wall 34 to the drum 2t and together with the end portion 4 4 of the sheet guide member 12, forms a sheet inlet 46 to the bin. The end portion. 44 and the bin guide plate 30 converge, as shown, to the inlet 46. From the sheet inlet 46, the guide plate 30 extends forwardly and joins the bin front wall 32 so as to form an acute angle with a plane 48 parallel to the stack follower 36 and an obtuse angle with the front Wall 32. As shown in FIG. 1, the plate 48 passes through the intersection. of plate 30 and wall 32. A bumper 50 may be inserted in the wall 32, as is known, at its intersection with guide plate 30. The processed sheets are projected by the drum 2t) and rollers 22 through the inlet 46, and along the guide plate 30, to the bumper 50. The exposed face of the bumper 5t and 3 the inner face of the Wall 32 form a registration edge 52 for the stack of documents. The documents are projected into the bin with sufficient force to wedge the stack along the registration edge 52.

In the system in which applioants invention is incorporated, pneumatic means is provided for deflecting an incoming sheet broadside out of the path of the next incoming sheet, by pivoting the trailing edge of the sheet around the leading edge on the bumper t An air head 54 having one or more outlet jets is located behind an opening in the guide plate 39, near the inlet 46, and an air stream ported to the jet or jets is directed into bin 2 toward the back-up member 36 to pivot the trailing edge of the document toward the stack. A pipe or tube 56 serves to port air to head 54 from any suitable compressed air system, not shown.

As shown in application Ser. No. 369,573, previously referred to, a power-driven paddle wheel or impeller 58 is provided near the inlet 46 and projects slightly into the bin 24 at the back Wall 34. The trailing edges of the incoming documents are deflected by the air stream into the teeth of impeller 58 and are thereby further propelled toward the stack of documents.

Applicants power-driven, rotating keeper 60 is positioned between the sheet propelling apparatus, i.e., the pneumatic deflecting means and the paddle wheel 58, and the stack of sheets pressed against the biased stack follower 36. As shown in FIGS. 2 and 3, the keeper 6% is in the form of a cylinder having a polygonal cross section, and extending laterally slightly into the bin 24 through the wall 34.

In FIG. 2 the impeller 58 and the keeper 6!) are shown as being affixed to upper end portions of vertical shafts 62 and 64', respectively. The shafts 62 and 54 are supported by conventional journals in casings 66 and 63 on base plate 26, One of the shafts, for example, shaft 62 in the embodiment shown, is power driven and drives the other shaft through a pulley and belt connection shown at 761. Both the impeller 58 and the keeper 6d are driven counterclockwise, as viewed in the figures, so that they urge sheets toward the stack follower 36.

In the illustrated system, the paddle wheel 58 is adjacent to the sheet inlet 46 on one side of the plane 48, whereas the keeper 661 is located on the other side of the plane 48 so as to be between the plane and the back-up member 36. The axes of rotation of the paddle wheel 58 and keeper 60 are on an arc (FIG. 3) which has its focal point coincident with the registration edge 52. The effect of this arrangement is to have the keeper 6t acting closely against the stack.

The function of the power-driven keeper 6% is to engage the edges of sheets fed to it by the paddle wheel 58 and to urge the sheets against the stackin bin 24. coincidentally, the rotating cylinder 60 serves to keep the sheets in stack formation by opposing the movement of previously stacked sheets back into engagement with the paddle wheel 58, while not tending to pull sheets out of alignment or battering the edges.

The particular configuration of cylinder 60 is the result of extensive experimentation and constitutes the main feature of the present invention. It has been found that a rapid and efiicient stacking operation may be achieved when the cylinder 60 has the cross-sectional shape of a regular polygon wherein the vertices thereof act to engage the sheets in bin 24. These vertices preferably protrude only slightly beyond the dedendum circle of the cylinder 6% so as to form low profile protuberances parallel to the axis of rotation of the cylinder. The protuberances of the keeper 66 are made large enough to adequately engage sheets being stacked and move them rapidly into a stacked position; however, the protuberances are small enough not to cause the sheets to creep out of registration. The number of vertices must be sufficient to prevent back-flow into the propelling apparatus. Extensive experimentation has shown that a cylinder with a hexagonal cross-section is the preferred embodiment. To further minimize abrasion against the sheets, the keeper 60 is preferably fabricated of plastic, as nylon, rather than metal.

Although the keeper 6'0 is preferably of hexagonal crosssection and has been described as acting only on one edge of a sheet, it is apparent that the scope of the invention includes cylinder configurations which have low profile protuberances axi-symmetrically distributed about their peripheries and may be used as keepers on one or more edges of sheets. However, it has been found that cylinders having only a few projections, for example those with triangular or square cross-sections, While workable, are not very efficient in the stacking operation and may allow sheets to accumulate between the propelling apparatus and the keeper. If the cylinder 60 has too many low profile protuberances it may act merely as a roller and fail tot interact adequately with the edges of the sheets.

I claim:

1. In a sheet stacker having means for advancing sheets singly and on edge into a bin and propelling them broadside toward a stack, the improvement comprising a power-driven rotating keeper acting on edges of advanced sheets propelled toward said stack for further urging said sheets into said stack and for keeping said sheets from retrogressing toward said propelling means, said keeper being in the form of a cylinder having a polygonal crosssection and extending laterally into said bin.

2. The power-driven rotating keeper of claim 1 wherein said polygonal cross-section is a regular hexagon.

3. In a bin for stacking sheets on edge, said bin having a stack back-up member biased toward the stack, high speed stacking apparatus comprising pneumatic means for propelling said sheets broadside toward said back-up member, power-driven impeller means for further propelling said sheets toward said stack, and power-driven rotating keeper means for urging said sheets into said stack and for preventing said sheets from retrogressing into said impeller means, said keeper means being in the form of a cylinder having a regular polygonal cross-section, the vertices of said rotating cylinder interacting with edges of said sheets. 4. The power-driven rotating keeper of claim 3 wherein said regular polygonal cross-section is a hexagon.

References Cited UNITED STATES PATENTS 3,220,724 11/1965 Von Glahn 271-68 FOREIGN PATENTS 712,608 7/1954 Great Britain.

M. HENSON WOOD, JR., Primary Examiner.

I. N. ERLICH, Assistant Examiner. 

1. IN A SHEET STACKER HAVING MEANS FOR ADVANCING SHEETS SINGLY AND ON EDGE INTO A BIN AND PROPELLING THEM BROADSIDE TOWARD A STACK, THE IMPROVEMENT COMPRISING A POWER-DRIVEN ROTATING KEEPER ACTING ON EDGES OF ADVANCED SHEETS PROPELLED TOWARD SAID STACK FOR FURTHER URGING SAID SHEETS INTO SAID STACK AND FOR KEEPING SAID SHEETS FROM RETROGRESSING TOWARD SAID PROPELLING MEANS, SAID KEEPER BEING IN THE FORM OF A CYLINDER HAVING A POLYGONAL CROSSSECTION AND EXTENDING LATERALLY INTO SAID BIN. 